A CAL is a Client Access License, and when you run the SQL Server program on a computer, you have to have a separate CAL for each device that accesses the SQL Server. This type of licensing is one of a few different options set up by Microsoft. If you have an SQL Server set up and want to find out how many CALs you have installed on the server, you can do so by running a command on the server in the Command Prompt program.
Log in to the server that you want to find the number of CALs on.
Click "Start," click "All Programs" and then open the "Accessories" folder.
Click "Command Prompt" and then type "sqlserver.exe -q -cal" into the window.
Press "Enter" and the number of CALs assigned to the server is displayed in the window.